Magnetic media are used in various electronic devices such as hard disk drives and magnetoresistive random access memory (MRAM) devices. Hard-disk drives are the storage medium of choice for computers and related devices. They are found in most desktop and laptop computers, and may also be found in a number of consumer electronic devices, such as media recorders and players, and instruments for collecting and recording data. Hard-disk drives are also deployed in arrays for network storage. MRAM devices are used in various non-volatile memory devices, such as flash drives and dynamic random access memory (DRAM) devices.
Magnetic media devices store and retrieve information using magnetic fields. The disk in a hard-disk drive is configured with magnetic domains that are separately addressable by a magnetic head. The magnetic head moves into proximity with a magnetic domain and alters the magnetic properties of the domain to record information. To recover the recorded information, the magnetic head moves into proximity with the domain and detects the magnetic properties of the domain. The magnetic properties of the domain are generally interpreted as corresponding to one of two possible states, the “0” state and the “1” state. In this way, digital information may be recorded on the magnetic medium and recovered thereafter.
Magnetic storage media typically comprise a non-magnetic glass, composite glass/ceramic, or metal substrate with a magnetically active material deposited thereon. The magnetically active material is generally either deposited to form a pattern, or is patterned after deposition, such that the surface of the device has areas of magnetic activity interspersed with areas of magnetic inactivity.
Recently, storage densities have increased, resulting in a migration from the historical method of patterning magnetic media according to concentric tracks toward a bit-patterned arrangement. The magnetically active layer, or a portion thereof, is subjected to a process that produces areas of magnetic activity like islands surrounded by areas of magnetic inactivity. Such methods are enabling progress in storage density beyond 1 TB/in2, but other challenges loom as the dimension of the islands shrinks.
More recent patterning methods rely on physical patterning, such as nanoimprint patterning, to produce a pattern having the requisite dimension. Such patterning relies on an imprintable medium that is frequently vulnerable to subsequent processing that transfers the pattern to subjacent layers. Pattern degradation during such subsequent processes may be extreme. Thus, there is a need for a process or method of patterning magnetic media, and an apparatus for performing the process or method efficiently for high volume manufacturing.